Titania Substrate Research Articles

Bactericidal and wound disinfection efficacy of nanostructured titania

Infections are caused due to the infiltration of tissue or organ space by infectious bacterial agents, among which Staphylococcus aureus bacteria are clinically most relevant. While current treatment modalities are in general quite effective, several bacterial strains exhibit high resistance to them, leading to complications and additional surgeries, thereby increasing the patient morbidity rates. Titanium dioxide is a celebrated photoactive material and has been utilized extensively in antibacterial functions, making it a leading infection mitigating agent. In view of the property amelioration in materials via nanofication, free-standing titania nanofibers (pure and nominally doped) and nanocoatings (on Ti and Ti6Al4V implants) were fabricated and evaluated to assess their efficacy to mitigate the viability and growth of S. aureus upon brief (30 s) activation by a portable hand-held infrared laser. In order to gauge the effect of exposure and its correlation with the antibacterial activities, both isolated (only titania substrate) and simultaneous (substrate submerged in the bacterial suspension) activations were performed. The bactericidal efficacy of the IR-activated <TEX>$TiO_2$</TEX> nanocoatings was also tested against E. coli biofilms. Toxicity study was conducted to assess any potential harm to the tissue cells in the presence of photoactivated materials. These investigations showed that the photoactivated titania nanofibers caused greater than 97% bacterial necrosis of S. aureus. In the case of titania-coated Ti-implant surrogates, the bactericidal efficacy exceeded 90% in the case of pre-activation and was 100% in the case of simultaneous-activation. In addition to their high bactericidal efficacy against S. aureus, the benignity of titania nanofibers and nanocoatings towards tissue cells during in-vivo exposure was also demonstrated, making them safe for use in implant devices.

RETRACTED: Heterogeneous photo-enhanced conversion of carbon dioxide to formic acid with copper- and gallium-doped titania nanocomposites

Copper- and gallium-doped titania photocatalysts prepared by means of sol–gel technique were comparatively evaluated with commercial TiO_2 (P25) for the photo-reduction of carbon dioxide to formic acid. The laboratory-made Cu_x–Ga_(1−x)/TiO_2 nanocomposites have been thoroughly characterized in crystallographic, structural, morphological, and elemental composition analyses. XRD revealed photocatalysts owning the specific crystalline phases of anatase, β-Ga_2O_3 and Cu_2O, which allowed inferring on the doping phenomena of both transition and post-transition metals. The quasi-homogeneous deposition of a Ga and Cu layer has been identified from the TEM morphological characterization and the Brunauer–Emmett–Teller and Barrett–Joyner–Halenda techniques unveiled quantitative differences in textural properties among the mesoporous Ga- and Cu-doped titania photocatalysts by underlining a decrease of surface area when augmenting the gallium dose. The laboratory-made photocatalysts presented bandgaps higher than 3 eV and the DRS spectra underlined the optical absorption edge of the nanocomposites with a considerable shift to the visible light region. The elemental composition quantified by means of XPS reproduced the binding energies relative of Ti, Cu and Ga (2p_(3/2), 2p_(1/2)), and the K-edge XANES characterization confirmed the effective doping and modulation of the electronic properties of the laboratory-made photocatalysts. Several experimental runs have been carried out with Cu_(0.78)–Ga_(0.22)/TiO_2 exhibiting the highest formic acid yields (394 μmol/g_(cat)) as well as superior quantum efficiency (49%) and selectivity (0.84). Accordingly, the photo-reduction of CO_2 was considerably promoted by doping Ga and Cu into the titania substrate, which ultimately avoided the surface recombination of electron–hole pairs, thereby enhancing the photo-activity of Cu_x–Ga_(1−x)/TiO_2 nanocomposites.

Formation of N719 Dye Multilayers on Dye Sensitized Solar Cell Photoelectrode Surfaces Investigated by Direct Determination of Element Concentration Depth Profiles

The structure of the dye layer adsorbed on the titania substrate in a dye-sensitized solar cell is of fundamental importance for the function of the cell, since it strongly influences the injection of photoelectrons from the excited dye molecules into the titania substrate. The adsorption isotherms of the N719 ruthenium-based dye were determined both with a direct method using the depth profiling technique neutral impact collision ion scattering spectroscopy (NICISS) and with the standard indirect solution depletion method. It is found that the dye layer adsorbed on the titania surface is laterally inhomogeneous in thickness and there is a growth mechanism already from low coverage levels involving a combination of monolayers and multilayers. It is also found that the amount of N719 adsorbed on the substrate depends on the titania structure. The present results show that dye molecules in dye-sensitized solar cells are not necessarily, as presumed, adsorbed as a self-assembled monolayer on the substrate.

Removal of Uranium(VI), Lead(II) at the Surface of TiO2 Nanotubes Studied by X-Ray Photoelectron Spectroscopy

A thin film of well-ordered anatase TiO2 nanotubes prepared by anodic oxidation of titanium metal were synthesised and used as adsorbent medium for the purification of water from aqueous uranium and lead. The amount of subtracted metal ions was quantified by using X-ray photoelectron spectroscopy at the surface of the reacted TiO2 surface. Batch experiments for the sorption of U and Pb at the surface of the titania substrate were carried out in separated solution equilibrated with air of uranyl acetate and lead nitrate, in the pH range 3–9. For uranium, the experiments were also repeated in anoxic (N2) atmosphere. The amount of metal ions adsorbed onto the titania medium was quantified by measurements of the surface coverage expressed in atomic percent, by recording high-resolution XPS spectra in the Ti2p, U4f and Pb4f photoelectron regions. Adsorption of the uranyl species in air atmosphere as a function of pH showed an adsorption edge near pH 4 with a maximum at pH 7. At higher pH the presence of very stable uranyl–carbonate complexes prevented any further adsorption. Further adsorption increased until pH 8.5 was obtained when the uranyl solution was purged from dissolved CO2. Lead ion showed a sorption edge at pH 6, with a maximum uptake at pH 8. The results showed that the uptake of uranium and lead on the selected titania medium is remarkably sensitive to the solution pH. This study demonstrates the reliability of this type of material for treating water polluted with heavy metals as well as leachates from radioactive nuclear wastes.

Dialkyldithiophosphate Acids (HDDPs) as Effective Lubricants of Sol–Gel Titania Coatings in Technical Dry Friction Conditions

The goal of this study was the investigation of the effectiveness of dialkyldithiophosphate acids (HDDPs) films in improving the tribological properties of thin, sol–gel derived titania coatings. Amorphous, anatase, and rutile titania coatings were obtained using sol–gel dip–coating deposition after treatment at 100, 500, and 1,000 °C, respectively. Titania coatings were then modified from the liquid phase by HDDPs acids having dodecyl-(C12), tetradecyl-(C14), and hexadecyl-(C16) alkyl chains deposited by dip–coating (DC) and Langmuir–Blodgett (LB) methods. The influence of the deposition procedure, the length of the HDDPs alkyl chain and the type of titania substrate on the surface morphology and tribological properties were studied. It was found, using wetting contact angle measurements, that these modifications of titania coatings decrease the surface free energy and increase its hydrophobicity. The surface topography imaged by Atomic force microscopy (AFM), exhibit island-like or agglomerate features for the DC deposition method, while smooth topographies were observed for LB depositions. Tribological tests were conducted by means of a microtribometer operating in the normal load range 30–100 mN. An enhancement of tribological properties was observed upon modification, as compared to unmodified titania.

Single-molecule switching with non-contact atomic force microscopy

We report upon controlled switching of a single 3,4,9,10-perylene tetracarboxylic diimide derivative moleculeon a rutile TiO2(110) surface using a non-contact atomic force microscope at room temperature. Aftersubmonolayer deposition, the molecules adsorb tilted on the bridging oxygen row.Individual molecules can be manipulated by the atomic force microscope tip in awell-controlled manner. The molecules are switched from one side of the rowto the other using a simple approach, taking benefit of the sample tilt and thetopography of the titania substrate. From density functional theory investigationswe obtain the adsorption energies of different positions of the molecule. Theseadsorption energies are in very good agreement with our experimental observations.

Nanoparticulate silver coated-titania thin films—Photo-oxidative destruction of stearic acid under different light sources and antimicrobial effects under hospital lighting conditions

Antimicrobial films containing silver nanoparticles on a titania substrate were prepared and shown to have marked visible light photocatalytic properties. The films could be transformed from purple (silver oxide) to orange (silver) by 254 nm, 365 nm or white light radiation and the process reversed when the films were stored in air and in the dark. The films were characterized by XRD, Raman, AFM, SEM, EDX, UV–Vis spectroscopy and XPS as well as tested for functionality using a range of techniques including water contact angle measurement, the photo-destruction of stearic acid to a range of light sources and antimicrobial activity against MRSA and Escherichia coli bacteria under hospital lighting conditions. XRD and Raman indicated that the films were anatase, X-ray photoelectron measurements confirmed the presence of silver loading on the titania surface and EDX showed silver doping in the TiO 2 layer. There appears to be an interaction between the phonon resonance of the silver nanoparticles and the band onset of the titania leading to significant visible light photo-oxidation of stearic acid as well as visible light induced superhydrophilicity. Samples were tested for photo-degradation of stearic acid under three different lighting conditions: UVA – 365 nm, white light (commonly found in UK hospitals) and UVA filtered white light. The Ag oxide-titania films were seen to be active photocatalysts under visible light conditions as well as displaying white light induced superhydrophilicity. These surfaces demonstrated a 99.996% reduction in the number of viable E. coli bacteria due to the silver ion presence and a 99.99% reduction in the number of MRSA bacteria due to the enhanced photocatalysis in a double pronged approach to antimicrobial mechanisms consisting of a synergistic relationship between the photocatalyst (TiO 2) and the surface bound silver nanoparticles.

Synthesis, characterization and application of sol–gel derived mesoporous TiO 2 nanoparticles for dye-sensitized solar cells

Nanocrystalline mesoporous titania of anatase crystal phase were prepared by sol–gel route by varying calcination (400 °C and 600 °C) conditions, and the photo-electrochemical properties were investigated for dye-sensitized solar cell applications. The TTIP precursor in n-heptane solvent with ratio of water to TTIP (5:1) was found to be effective substrate for the working electrodes. The overall conversion efficiency of 7.59% was achieved under 1 sun irradiation with open circuit voltage of 0.77 V, current density of 17.00 mA/cm 2 and FF of 51.12. The high efficiency of the 400 °C calcined sample were attributed to its mesopores, high BET surface area (80.1 m 2/g) and large pore volume of prepared titania substrate which provide better surface for the absorption of dye, improves light harvesting efficiency and better charge injection. The prepared samples were characterized by XRD, small angle XRD, FE-SEM, TEM, IPCE, I– V curve, BET surface area and BJH plot techniques.

Theoretical Study of the Effect of (001) TiO2Anatase Support on V2O5

The effect of (001) TiO2 anatase support on the electronic and catalytic properties of a V2O5 monolayer is analyzed using density functional theory (DFT). The catalyst is represented by both clusters and periodic slabs. Using two experimentally relevant models of monolayer V2O5/TiO2 (anatase) catalyst, both weak and strong interactions between a V2O5 monolayer and the TiO2 support have been investigated. In the first model, where a crystallographic (001) V2O5 layer is placed on top of the (001) TiO2 support, the weak interaction between vanadia and titania does not result in a major reconstruction of the active phase. Nevertheless, the changes in the electronic properties of the system are evident. The deposition of the vanadia monolayer on the titania substrate results in charge redistribution, enhancing the Lewis acidity of vanadium and the chemical hardness above the vanadyl oxygen, and in a shift of the Fermi level to lower binding energies accompanied by a reduction in the band gap. In the second mod...

Facile synthesis of nanostructured hydroxyapatite–titania bio-implant scaffolds with different morphologies: their bioactivity and corrosion behaviour

A facile synthesis to fabricate HAp–titania scaffolds with different morphological features has been presented. The hydrothermal approach explored for HAp growth leads to the formation of HAp coating onto titania substrate with distinct morphological features such as cauliflower, urchin, porous nanofibres network, nanorods, etc. under different reaction microenvironments. The XRD analysis done for all HAp–titania scaffold samples revealed the formation of hydroxyapatite phase. Furthermore, the detailed FTIR, SAED and EDS analysis performed confirmed the formation of hydroxyapatite. The addition of H2O2 to the reaction mixture led to the high degree of self-assembly of the formed nanosheets into urchin or consolidated sphere like structures when NaOH or KOH was used in hydrothermal reaction, respectively. The detailed TEM analysis reveals that the formation of such HAp structures takes place by (i) formation of localized corrosion sites on titanium substrate with NaOH/KOH and (ii) the subsequent recrystallization of HAp sol onto the corrosion sites which act as nucleation site. The Tafel plot measurements and MTT assay test indicate that the HAp–titania scaffold samples are corrosion resistance as compared to bare titanium foil and are biocompatible. The structural characterization, growth mechanism, corrosion behaviour in SBF medium and cellular biocompatibility of these scaffold samples are discussed in detail.

Gold, Copper, and Platinum Nanoparticles Dispersed on CeOx/TiO2(110) Surfaces: High Water-Gas Shift Activity and the Nature of the Mixed-Metal Oxide at the Nanometer Level

At small coverages of ceria on TiO(2)(110), the CeO(x) nanoparticles have an unusual coordination mode. Scanning tunneling microscopy and density-functional calculations point to the presence of Ce(2)O(3) dimers, which form diagonal arrays that have specific orientations of 0, 24, and 42 degrees with respect to the [1 -1 0] direction of the titania substrate. At high coverages of ceria on TiO(2)(110), the surface exhibits two types of terraces. In one type, the morphology is not very different from that observed at low ceria coverage. However, in the second type of terrace, there is a compact array of ceria particles with structures that do not match the structures of CeO(2)(111) or CeO(2)(110). The titania substrate imposes on the ceria nanoparticles nontypical coordination modes, enhancing their chemical reactivity. This phenomenon leads to a larger dispersion of supported metal nanoparticles (M = Au, Cu, Pt) and makes possible the direct participation of the oxide in catalytic reactions. The M/CeO(x)/TiO(2)(110) surfaces display an extremely high catalytic activity for the water-gas shift reaction that follows the sequence Au/CeO(x)/TiO(2)(110) < Cu/CeO(x)/TiO(2)(110) < Pt/CeO(x)/TiO(2)(110). For low coverages of Cu and CeO(x), Cu/CeO(x)/TiO(2)(110) is 8-12 times more active than Cu(111) or Cu/ZnO industrial catalysts. In the M/CeO(x)/TiO(2)(110) systems, there is a strong coupling of the chemical properties of the admetal and the mixed-metal oxide: The adsorption and dissociation of water probably take place on the oxide, CO adsorbs on the admetal nanoparticles, and all subsequent reaction steps occur at the oxide-admetal interface. The high catalytic activity of the M/CeO(x)/TiO(2)(110) surfaces reflects the unique properties of the mixed-metal oxide at the nanometer level.

Chemical Growth and Photochromism of Silver Nanoparticles into a Mesoporous Titania Template

Elaboration of mesoporous titanium oxide film supporting silver nanoparticles is described. Mesoporous titanium oxide films are characterized by TEM analysis. Titania films are infiltrated with a silver salt solution and chemical reduction treatments are performed using either a NaBH(4) or a formaldehyde solution. Infiltrated films are then characterized by TEM, SEM, AFM, UV-visible spectroscopy, X-ray diffraction, and Rutherford Backscattering Spectrometry (RBS). The utilization of a mesoporous titania substrate allows to control the nanoparticle size and the interparticle distance. RBS experiments provide the evidence that NaBH(4) treatment induces a strong accumulation of silver nanoparticles in the subsurface of the layer, while formaldehyde treatment induces the formation of silver nanoparticles embedded into almost the whole depth of the titania film. Large silver nanocrystals are also formed at the film surface whatever the reducer used. A broad visible absorption band related to the surface plasmon resonance (SPR) is obtained in both cases and is strongly red-shifted compared to the SPR obtained for silver nanoparticles inside a silica matrix. Moreover, irradiation with visible light causes the photooxidation of silver nanoparticles by titania and a complete discoloration of the material. The photooxidation is related to a drastic decrease in the silver nanoparticle size and is found to be reversible, particularly in the case of the material obtained by the formaldehyde reduction.

High catalytic activity of Au/CeOx/TiO2(110) controlled by the nature of the mixed-metal oxide at the nanometer level.

Mixed-metal oxides play a very important role in many areas of chemistry, physics, materials science, and geochemistry. Recently, there has been a strong interest in understanding phenomena associated with the deposition of oxide nanoparticles on the surface of a second (host) oxide. Here, scanning tunneling microscopy, photoemission, and density-functional calculations are used to study the behavior of ceria nanoparticles deposited on a TiO(2)(110) surface. The titania substrate imposes nontypical coordination modes on the ceria nanoparticles. In the CeO(x)/TiO(2)(110) systems, the Ce cations adopt an structural geometry and an oxidation state (+3) that are quite different from those seen in bulk ceria or for ceria nanoparticles deposited on metal substrates. The increase in the stability of the Ce(3+) oxidation state leads to an enhancement in the chemical and catalytic activity of the ceria nanoparticles. The codeposition of ceria and gold nanoparticles on a TiO(2)(110) substrate generates catalysts with an extremely high activity for the production of hydrogen through the water-gas shift reaction (H(2)O + CO --> H(2) + CO(2)) or for the oxidation of carbon monoxide (2CO + O(2) --> 2CO(2)). The enhanced stability of the Ce(3+) state is an example of structural promotion in catalysis described here on the atomic level. The exploration of mixed-metal oxides at the nanometer level may open avenues for optimizing catalysts through stabilization of unconventional surface structures with special chemical activity.

Photocatalytic printing of inorganic nanopatterns via poly(styrene-block-carbosilane) copolymer thin films on titania substrates

Well-defined, ordered arrays of nanoscale depressions were obtained in linear-brush-type polystyrene-block-polycarbosilane (PS-b-PCS) diblock copolymer thin films by acetone vapor annealing and silica nanodot arrays were directly obtained from such thin films deposited on a titania substrate by one-step exposure to UV light as a result of transformation of the PCS units to silica, driven by the photocatalytic activity of titania concurrent with removal of the organic matrix.

Functional Fe3O4/TiO2 Core/Shell Magnetic Nanoparticles as Photokilling Agents for Pathogenic Bacteria

A photokilling approach for pathogenic bacteria is demonstrated using a new type of magnetic nanoprobe as the photokilling agent. In addition to their magnetic property, the nanoprobes have other features including a photocatalytic property and the capacity to target bacteria. The nanoprobes comprise iron oxide/titania (Fe(3)O(4)@TiO(2)) core/shell magnetic nanoparticles. As dopamine molecules can self-assemble onto the surface of the titania substrate, dopamine is used as the linker to immobilize succinic anhydride onto the surfaces of the Fe(3)O(4)@TiO(2) nanoparticles. This is followed by the immobilization of IgG via amide bonding. We demonstrate that the IgG-Fe(3)O(4)@TiO(2) magnetic nanoparticles not only have the capacity to target several pathogenic bacteria, but they also can effectively inhibit the cell growth of the bacteria targeted by the nanoparticles under irradiation of a low-power UV lamp within a short period. Staphylococcus saprophyticus, Streptococcus pyogenes, and antibiotic-resistant bacterial strains, such as multiantibiotic-resistant S. pyogenes and methicillin-resistant Staphylococcus aureus (MRSA), are used to demonstrate the feasibility of this approach.

Performance enhancement in the water–gas shift reaction of platinum deposited over a cerium-modified TiO2 support

A novel catalyst consisting of platinum deposited over a cerium-modified titania substrate has been studied. Pt supported on Ce-modified TiO2 catalyt shows better thermal stability respect to bare TiO2 support and higher WGS activity than those corresponding to individual titania and ceria supports, indicating a cooperative effect between Pt and the Ce-modified TiO2 support. XPS and TPR results revealed the intimate contact between Pt and cerium entities in the Pt/Ce–TiO2 catalyst that facilitates the reducibility of the support at low-temperatures while the Ce–O–Ti surface interactions established in the Ce-modifed support TiO2 decrease the overreduction of TiO2 at high-temperature. Comparison of catalytic activity with catalysts characterization suggests that the modifications in the reducibility of the support and the stability of metallic particles when platinum is supported on cerium-modified TiO2 are responsible of the better catalytic behaviour of this sample in the water–gas shift reaction.

Cellulose Nanocrystal Submonolayers by Spin Coating

Dilute concentrations of cellulose nanocrystal solutions were spin coated onto different substrates to investigate the effect of the substrate on the nanocrystal submonolayers. Three substrates were probed: silica, titania, and amorphous cellulose. According to atomic force microscopy (AFM) images, anionic cellulose nanocrystals formed small aggregates on the anionic silica substrate, whereas a uniform two-dimensional distribution of nanocrystals was achieved on the cationic titania substrate. The uniform distribution of cellulose nanocrystal submonolayers on titania is an important factor when dimensional analysis of the nanocrystals is desired. Furthermore, the amount of nanocrystals deposited on titania was multifold in comparison to the amounts on silica, as revealed by AFM image analysis and X-ray photoelectron spectroscopy. Amorphous cellulose, the third substrate, resulted in a somewhat homogeneous distribution of the nanocrystal submonolayers, but the amounts were as low as those on the silica substrate. These differences in the cellulose nanocrystal deposition were attributed to electrostatic effects: anionic cellulose nanocrystals are adsorbed on cationic titania in addition to the normal spin coating deposition. The anionic silica surface, on the other hand, causes aggregation of the weakly anionic cellulose nanocrystals which are forced on the repulsive substrate by spin coating. The electrostatically driven adsorption also influences the film thickness of continuous ultrathin films of cellulose nanocrystals. The thicker films of charged nanocrystals on a substrate of opposite charge means that the film thickness is not independent of the substrate when spin coating cellulose nanocrystals in the ultrathin regime (<100 nm).

Atomic-Scale Study of in Situ Metal Nanoparticle Synthesis in a Ni/TiO2 System

The nucleation and evolution of Ni nanoparticles during reduction of a Ni(NO3)2.6H2O precursor supported on a commercial titania substrate have been studied in situ at atomic resolution using environmental transmission electron microscopy. An incipient wetness technique was used to prepare the starting unreduced material (10 wt % Ni precursor on titania). The Ni precursor, before reduction, shows a nonuniform distribution over the titania support. It is observed that upon reduction, the initial Ni "seed" crystal nucleates within the precursor patch. The distribution and size of the Ni nanoparticles thus generated are influenced by the distribution and size of the precursor patches. In this system, we see no evidence of preferential nucleation of Ni particles on anatase or rutile. At 350 degrees C with CO as the reducing agent, the {111} surface facets of the Ni nanoparticles are predominant during the initial stage of nucleation and growth. However, the {111} facets are partially consumed with time, indicating that they are not thermodynamically favored in the CO atmosphere. In CO and H2 atmospheres, Ni particles show a nonwetting morphology on titania, while in a mild oxidizing environment, a thin layer of NiOx is formed, thus giving rise to a morphology that is indicative of wetting of the support. This work provides fundamental information on understanding and controlling the important parameters involved in the preparation of a well-designed supported Ni catalyst using the incipient wetness technique.

The growth of ultrathin films of vanadium oxide on TiO2()

Abstract The growth morphology of ultrathin (up to 5 ML) vanadium oxide films on TiO2(1 1 0) has been investigated by scanning tunneling microscopy (STM) and low-energy electron diffraction (LEED). It has been found that the reactive evaporation technique produces more uniform and better-ordered vanadia layers than the post-oxidation method. At low coverages V-oxide clusters adsorb on top of the fivefold-coordinated Ti rows of the substrate. With increasing coverage the clusters agglomerate and form strands, which are oriented along the [0 0 1] titania direction. For oxide coverage >2 ML the strands cover uniformly the titania substrate, forming a texture along the [0 0 1] direction, and give rise to a (1 × 1) LEED pattern. The latter is consistent with the growth of an epitaxial rutile-type VO2 phase.

Improvement of photocatalytic efficiency of rutile titania by silver negative-ion implantation

Optical absorption and photocatalytic properties of metal negative-ion implanted rutile-type titania (TiO 2) were studied to show metal nanoparticle formation in the surface region and improvement of photocatalytic efficiency. Silver negative ions were implanted into titania substrate (rutile crystalline substrate) at 65 keV with a dose of 3 × 10 16–1 × 10 17 ions/cm 2. The Ag-implanted rutile also showed a strong optical absorption near 2.1 eV after annealing above 400 °C, those well agreed with theoretical absorption peaks due to surface plasmon resonance. This means that Ag nanoparticles were formed in the surface layers of the titania. Photocatalytic efficiencies for Ag-implanted titania were evaluated by means of decolorization of methylene blue solution under fluorescent light. Ag-implanted titania (Ag: 65 keV, 5 × 10 16 ions/cm 2, 500 °C annealed) showed the better photocatalytic efficiency higher 2.2 times than that of unimplanted rutile titania. In the evaluation under fluorescent light through UV-cut filter, the Ag-implanted rutile showed 6.7 times better efficiency.